1. Field of the Invention
The present invention relates to a method and an apparatus for allocating a channel to a wireless interface, and more particularly, to a method and an apparatus for allocating a channel for minimizing interference between channels in a node on an Ad-hoc network which uses a plurality of wireless interfaces for communication.
2. Description of Related Art
Since all nodes in an 802.11 based Ad-hoc network use the same wireless channel, the performance of the network deteriorates due to channel interference which occurs in transmitting a packet between the nodes. Accordingly, a method of two-channel communication by using the nodes having two wireless interfaces in the network and different channels allocated to the wireless interfaces has been developed for improving a usage rate of each of the channels and decreasing interference between the channels.
FIG. 1 is a diagram illustrating conventional technology for allocating channels to a wireless interface. As illustrated in FIG. 1, a wireless link is formed between two nodes of Node A, Node B, Node C, and Node D. Each of the nodes has two wireless interfaces and communicates with each other using first and second channels. The first and second channels are allocated permanently to each wireless interface of one of the nodes. In other words, when a node turns on, the first and second channels which have been already formed are allocated to each of the two wireless interfaces. For example, when the node A communicates with the node C, the nodes A and C determine which channel between the first and second channels is to be used.
If a communication status of the first channel is better, the first channel is used for communication. At this time, selection of a channel is related to which channels are used between neighbor nodes. In other words, when a communication status of the first channel deteriorates due to channels used between the nodes A and D, the nodes A and B, the nodes C and B, and the nodes C and D, the nodes A and C detect the communication status of the first channel and communicate with each other using the second channel.
According to the conventional technology described above, every node allocates channels permanently to a wireless interface and determines which channel of the allocated channels is to be used. In other words, since every node allocates permanently and uses the same two channels even when there are more channels available, the usage rate of the channels is still low. Therefore, the interference between the channels remains problematic. If a node has as many wireless interfaces as the number of channels available, the problem described above may be solved. However, this method is not desirable in terms of cost of the required hardware.